Land and sea search underway at Jervis Bay for missing fisherman

Police have scaled back the search for a fisherman feared drowned at Jervis Bay on the New South Wales south coast.

The man believed to be from north west Sydney went missing around 2.30am (AEDT) this morning.

The three friends he was fishing with alerted authorities that he had fallen from rocks at Mermaids Inlet near Currarong.

NSW Marine Rescue controller Bruce Mitchell says the man's friends did what they could to help him.

"There was a life ring (rescue device) thrown in to the person that was in the water, that life ring was located along with a small eskie," he said.

Joanne Elliot from Police Media says additional resources were brought in to help find the man, including the Port Kembla Water Police, Marine Rescue volunteers, volunteers from the Surf Lifesavers as well as the police helicopter PolAir.

She says police are not sure if the man was wearing a lifejacket.

"...We're hoping it will be positive outcome, unfortunately we don't have any indication he was wearing a life vest," she said.

Surf life savers have been brought back to shore as conditions on the water deteriorate. Police say it is also too dangerous at this stage to deploy divers to help with the search